1. Field of the Invention
Embodiments of the present invention relate to catheter technology and, in particular, to modular catheter systems having removable catheter portions.
2. Description of Related Art
The use of implantable devices to remedy medical conditions is becoming increasingly frequent as the size and cost of such devices shrinks and as the devices become easier to use. Many patients who, in the past, were forced to make routine visits to a medical professional for treatment or analysis or who were forced to self-administer treatment now rely on implanted devices to treat and analyze various medical conditions, thereby alleviating or eliminating the burden of trips to the hospital or doctor's office and the physical and emotional difficulty of rendering treatment to oneself. The use of implantable devices has given many patients the freedom they once new before the onset of their medical conditions, or perhaps the freedom they've never known for those who have dealt with medical conditions their entire lives.
For example, many people with diabetes now rely on implanted infusion pumps to deliver insulin. Implanted infusion pumps, along with associated sensing and control electronics, are capable of determining an amount of insulin required by a patient and can deliver a bolus or basal rate of insulin. Frequent manual testing of blood glucose levels has been replaced by glucose sensing technology included with the pump. Also, the routine injection of insulin by the patient using a needle has been replaced by the internal delivery of insulin by the pump based on the glucose levels determined by the sensor. Accordingly, diabetic patients who have taken advantage of implanted infusion pumps enjoy a lifestyle similar to that enjoyed by non-diabetics.
Most implanted devices include catheters for a variety of reasons. For example, implanted catheters may be used to deliver an infusant, such as a drug or other medicant, or may be used to provide a path for sensing technology or electronic signals. Currently, many catheters used in conjunction with implantable devices, such as an implantable infusion pump, for example, typically connect directly to the implantable device, as can be seen in the pump-catheter system 2 shown in FIG. 1. In FIG. 1, a catheter 8 is a right-angled catheter that makes a direct connection into an implantable infusion pump 4 at a connection point 6. When the catheter 8 needs to be replaced, the entire catheter 8 is removed at the connection point 6. Although connecting the catheter directly to the implantable device appears to be a logical, simple way to make a connection to the device, in practice, such a connection can actually be inefficient and even detrimental to a patient.
For example, if an implantable pump is placed into a patient, a pocket of tissue, i.e., a “pump pocket,” forms around the pump and, consequently, the interface between the pump and the catheter as well. Generally, if the catheter includes a sensor, the catheter will need replacement more often than the pump needs to be replaced or needs to be serviced. To replace the catheter, then, requires that the pump pocket be opened, a procedure that is time consuming and undesirable. Once a pump pocket forms, opening it may be traumatic for the patient, time consuming for both patient and doctor, expensive and can increase the risk of infection. Also, opening a pump pocket requires a hospital stay for the procedure and for observation. Thus, although connecting a catheter directly to an implantable device appears reasonable, a connection of this type is actually fraught with ramifications that work toward the detriment of the patient and the patient's care providers.
In addition, many catheters made today that are suitable for implantation are labor intensive from a manufacturing standpoint and costly from a sterilization standpoint. For example, catheters that are used in complex applications can themselves be complex devices requiring sophisticated, expensive parts. Moreover, many of these parts are sensitive, such as the polyethylene tubing used in some catheters, and must be sterilized using a sensitive technique such as EtO sterilization, for example. In order for implantable devices to be considered a routine prescription for the remedying of debilitating medical conditions, the catheters used in conjunction with such devices must themselves be manufacturing friendly and must interface with the implantable devices in such a way catheter replacement is not a risky, expensive time consuming procedure.